The U.S. Supreme Court will begin three days of hearings Monday on the complex economic and legal issues surrounding the Patient Protection and Affordable Care Act, which revamps the $2.6 trillion health care industry.

Here is a look at the four issues the justices will review:

Monday – The justices will hear arguments about whether it is too soon to consider legal challenges to the mandate to purchase insurance. The question revolves around whether the mandate’s financial penalty is considered a tax. Federal law bars challenges to taxes until they are paid. Because the financial penalties won’t be assessed until 2014, an appeals court has ruled that the challenge is premature.

This issue has drawn the least public attention, but it could be crucial to the outcome of the cases, says Lyle Denniston, in Bloomberg Law’s SCOTUS blog.
“If lawsuits turn out to have been barred, the mandate may not be challenged probably until 2015 at the earliest,” he writes.

Both the Obama administration and the law’s opponents want the court to decide the cases now. But one federal appeals court has ruled the cases are premature, and the justices have appointed an attorney to argue that point.

Tuesday – The hearing will focus on the most controversial element of the Affordable Care Act: the mandate for most individuals to buy health insurance. The 26 states challenging it (including Michigan) and the National Federation of Independent Business argue the rule is an unconstitutional intrusion on individual liberty. The government contends it is allowed under Congress’ authority to regulate activities that affect interstate commerce and to make laws needed to execute other powers.

Wednesday – The hearings address two issues:

• The justices will hear arguments on whether the rest of the Affordable Care Act must be overturned if the health insurance mandate is ruled unconstitutional. The opponents say the act could not take effect because the mandate is intertwined with the law’s other components. The government argues only two provisions would fall if the mandate is tossed out: the requirement that insurers cover people with preexisting conditions and that they not charge them higher premiums.

• The court also will consider whether the expansion of Medicaid is constitutional and whether the federal government can require states to comply by threatening to cut off Medicaid funding. The opponents argue the requirement exceeds federal authority. The government says participation in Medicaid is voluntary and that Congress has the constitutional power to require compliance as a condition of receiving funding.

SOURCES: The New England Journal of Medicine, Centers for Medicare and Medicaid Services and the SCOTUS blog sponsored by Bloomberg Law